全文获取类型
收费全文 | 599篇 |
免费 | 87篇 |
专业分类
686篇 |
出版年
2021年 | 12篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 19篇 |
2014年 | 24篇 |
2013年 | 33篇 |
2012年 | 28篇 |
2011年 | 33篇 |
2010年 | 30篇 |
2009年 | 16篇 |
2008年 | 23篇 |
2007年 | 14篇 |
2006年 | 19篇 |
2005年 | 20篇 |
2004年 | 28篇 |
2003年 | 12篇 |
2002年 | 23篇 |
2001年 | 19篇 |
2000年 | 15篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1994年 | 17篇 |
1993年 | 9篇 |
1992年 | 12篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 15篇 |
1987年 | 13篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 12篇 |
1972年 | 7篇 |
1971年 | 4篇 |
1968年 | 4篇 |
1956年 | 4篇 |
1954年 | 4篇 |
1952年 | 3篇 |
1951年 | 4篇 |
1950年 | 7篇 |
1949年 | 3篇 |
排序方式: 共有686条查询结果,搜索用时 15 毫秒
1.
2.
W J Allard C D Cheli D L Morris J Goldblatt Y Pierre L Kish Y Chen J Dai R L Vessella D W Chan M K Schwartz Z Zhou K K Yeung 《The International journal of biological markers》1999,14(2):73-83
We conducted a multicenter evaluation of the analytical and clinical performance of the automated Bayer Immuno 1 complexed PSA (cPSA) assay, and compared assay performance to the Bayer Immuno 1 PSA assay. We sought to determine whether measurements of cPSA could be of clinical utility in the management of patients with prostate cancer. Results of the 10-day imprecision across three evaluation sites produced total CV < 2.50% and an analytical sensitivity of 0.02 microgram/L. There was an increased trend in clinical sensitivity for prostate cancer with increasing stage of disease (71-86%). Clinical specificity for patients with benign urogenital disease was 74.8%, and for other nonprostate diseases ranged from 91.1-100%. Retrospective serial monitoring of 155 patients with prostate cancer demonstrated concordance of cPSA measurements to clinical status for 97% of the patients analyzed. Results from the clinical studies using the Bayer Immuno 1 cPSA assay were comparable to results obtained with the Bayer Immuno 1 PSA assay. The Bayer Immuno 1 cPSA assay demonstrates analytical performance and clinical effectiveness in the management of prostate cancer patients during the course of disease and therapy. 相似文献
3.
Ann-Sofie Allard Alasdair H Neilson 《International biodeterioration & biodegradation》1997,39(4):253-285
An overview is presented of the potential for bioremediation of a range of contaminated sites. Most of the compounds belong to groups that are widespread and are generally persistent or toxic. Although attention has been focused on microbiological aspects of their application, it is pointed out that a successful programme requires integrated input from geologists, engineers, chemists and microbiologists. It is emphasized that a protocol must be available for evaluating the success of the procedures that have been implemented. Attention is directed to critical issues, including partial degradation, formation of metabolites, and recalcitrance of specific components in complex mixtures. An attempt is made to discuss the basic aspects of the biodegradation of components specific to the various sites and to illustrate the outcome of experiments in bioremediation in laboratory-based, pilot-scale or full-scale field operations. Brief discussion is given of some less commonly perceived contaminants that may be present simultaneously. 相似文献
4.
J G Lehoux C Allard F Bouthillier S Bélisle D Bellabarba 《Journal of steroid biochemistry》1988,30(1-6):295-300
We have studied the properties of the nuclear receptors for aldosterone in kidneys of chick embryo. Aliquots of 0.4 M KCl nuclear extracts were incubated with [3H]aldosterone with or without 1 microM RU28362, a potent glucocorticoid analog. Scatchard analyses of binding data revealed two classes of binding sites with Ka of 0.26 and 0.03 X 10(9) M-1 and Nmax of 330 fmol and 620 fmol/mg DNA respectively. In presence of RU28362, however, we observed only a single class of binding sites with a Ka of 1.02 X 10(8) M-1 and a Nmax of 90 fmol/mg DNA. Competition studies performed in presence of RU28362 showed that aldosterone was the more effective competitor followed by corticosterone, progesterone, deoxycorticosterone, dexamethasone, cortisol, triamcinolone acetonide and cortisone. The nuclear complexes had a sedimentation coefficient in the area of 8 S which changed to 4-5 S in the presence of 0.4 M KCl. This effect of KCl was prevented by the addition of 10 mM sodium molybdate. Always in the presence of the glucocorticoid analog, by DEAE-c chromatography we observed a major specific aldosterone-binding fraction which was eluted with 0.2 M KCl. This fraction sedimented at 8.4 S in the absence of sodium molybdate and KCl. In the absence of RU28362, DNA-c columns retained only a small portion of the nuclear complexes which were eluted with KCl. These complexes sedimented, on sucrose gradient, at 4.6 and 3.1 S, whereas those which did not bind to DNA-c had a sedimentation coefficient of 8 S. In the presence of RU28362, the majority of bound [3H]aldosterone remained in the column flow-through fraction; when this fraction was further analyzed on DEAE-c, complexes were eluted with 0.2 and 0.3 M KCl. These data indicate that nuclear receptors for aldosterone are present in small number in kidneys of chick embryo and that they are mostly in the 8 S form. 相似文献
5.
6.
7.
8.
9.
Genetic and Molecular Organization of Ribosomal DNA (Rdna) Variants in Wild and Cultivated Barley 总被引:2,自引:2,他引:0 下载免费PDF全文
Twenty rDNA spacer-length variants (slvs) have been identified in barley. These slvs form a ladder in which each variant (with one exception) differs from its immediate neighbors by a 115-bp subrepeat. The 20 slvs are organized in two families, one forming an eight-step ladder (slvs 100-107) in the nucleolus organizer region (NOR) of chromosome 7 and the other a 12-step ladder (slvs 108a-118) in the NOR of chromosome 6. The eight shorter slvs (100-107) segregate and serve as markers of eight alleles of Mendelian locus Rrn2 and the 12 longer slvs (108a-118) segregate and serve as markers of 12 alleles of Mendelian locus Rrn1. Most barley plants (90%) are homozygous for two alleles, including one from each the 100-107 and the 108a-118 series. Two types of departures from this typical pattern of molecular and genetic organization were identified, one featuring compound alleles marked by two slvs of Rrn1 or of Rrn2, and the other featuring presence in Rrn1 of alleles normally found in Rrn2, and vice versa. The individual and joint effects on adaptedness of the rDNA alleles are discussed. It was concluded that selection acting on specific genotypes plays a major role in molding the strikingly different allelic and genotypic frequency distributions seen in populations of wild and cultivated barley from different ecogeographical regions. 相似文献
10.
Cronobacter has caused numerous illnesses in neonates, infants, and children. Here we report the draft genome of Cronobacter sakazakii E899. Whole-genome sequence analysis of Cronobacter strains provides a tool for understanding the genomic regions specific to each individual species. 相似文献